<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
	</head>
	<body>
		<script type="text/javascript">
			var num1 = 1;
			var num2 = 2;
			
			num1 = num1+num2;//3
			num2 = num1-num2;//1
			num1 = num1-num2;//2
			alert(num1);
			alert(num2);
		</script>
	</body>
</html>
